How does a Compass work?

A magnet will always point North-South direction, because it is attracted by the north and south magnetic poles of the planet Earth. This property is used in a compass. A small needle-like magnet with its north and south poles marked is balanced on a pivot. The pivot is placed in the centre of a card with all the directions (or points of the compass) marked on it. If a traveller or person positions the compass so that the needle lies along the north-south line on the card, he can read off the direction in which he is going.

Compass is very useful. For example, long ago in past, sailors of all around the World were navigate by using the Sun’s position in Daytime and Star’s position in Night time. But, sometimes, it was too cloudy for them to see the Sun or the Stars and so they did not know which way they have to go. The compass revolutionized sea travel because the sailors could find their way whatever the weather is. A compass needle points to the Earth`s magnetic poles. The navigator wants to know his direction in relation to the geographic poles. So he has to know the distance between the geographic and magnetic poles to correct his compass reading.

It is interesting to know that, who invented first compass is not clear but historians think that, Chinese civilization may have been first to develop a magnetic compass that could be used for navigation. Chinese scientists may have developed navigational compasses as early as the 11th or 12th century. Western Europeans soon followed at the end of the 12th century.